Introducing mercury into vacuum devices



June 30, 1942. E. A. REUTER I INTRODUCING MERCURY INTO VACUUM DEVICESFiled June 21, 1941 m L N WM Mm V T W N M Patented June 30, 1942 TETOFFICE Edmund A. Renter, East Orange, N. J., assignor to WestinghouseElectric in Manufacturing Company, East Pittsburgh, Pa, a corporation ofPennsylvania Application June 21, 1941, Serial No. 399,059

'7 Claims.

My invention relates to discharge devices, and especially to introducingmercury or other gaseous vapor into the container of such dischargedevices.

An object of the invention is to introduce a predetermined amount ofmercury or other gaseous medium into a discharge device. Heretofore, therequired amount of mercury has been distilled into discharge devices,such as lamps and electronic devices during manufacture or an excess ofmercury has been introduced into the lamp and the excess boiled outuntil the required amount is left.

My invention is a means of introducing measured amount of mercury into alamp or electronic device without the disadvantages of these oldermethods.

In particular, I incorporate the mercury or other gaseous medium in asealed container inserted in the assembled tube and then release themercury or other vapor by the use of high frequency after the tube hasbeen pumped out and sealed off.

In particular, my invention permits the ready release of the mercury atthe desired time and my preferred embodiment prevents any contaminationof air in the mercury introduced into the tube.

Other objects and advantages of my invention will be apparent from thefollowing description and drawing in which:

Fig. l is a partial view of one end of a sterilizing lamp in which apreferred embodiment of my invention has been incorporated.

Fig. 2 is an enlarged view of the mercury container illustrated in Fig.1.

Fig. 3 is a cross sectional view on lines IIIIII of Fig. 2.

Fig. 4 is a longitudinal cross section of one end of the mercurycontainer of Fig. 2.

Fig. 5 is a modification of the form of container illustrated in Fig. 2.

Figs. 6 through 12 are respectively still further modifications of myinvention.

In Fig. l I have illustrated one end of a sterilizing lamp to which myinvention has been applied. This lamp includes a glass casing II] havinga press II at one end through which extends the conductor I2 to theelectrode l3. A conductor I6 is connected to a standard I! coated withglass insulation l8 and passes upward to an electrode, not shown, butsimilar to E3 and cooperating therewith.

, In order to introduce the mercury into the device at the proper time,I provide a container 25! which is more fully illustrated in Fig. 2.This container is welded to a rod 2| welded in turn to one of the fins22 at the base of the electrode l3. The mercury container 20 ispreferably supported adjacent the press I l,wh'e re it can beconveniently flashed by a high frequency coil 23 surrounding the tube atthe location of the mercury container 29.

The mercury container 20 is a length of seamless metal tube, preferablynickel, with an outside diameter preferably of 25 to-30 mils, and a wallthickness of approximately 3 to 5 mils. The outside diameter ispreferably not over 35 mils. The tubing is filled with pure mercury andwith the desired quantity determined by the length of the tube. The twoends 2 5 and 26 of the nickel tubing, are welded shut which produces aflat portion at the end, and the tube is then formed into a circle on asuitable mandrel and the ends welded together, as disclosed in Fig. 2.

This welding operation can be done either as a separate operation, or atthe time the ring'is welded to the support wire or conductor 2|. Thesmall diameter tubing utilized in the preferred dimensions provide asimple operation in making a completely tight weld across the flattenedend. Because of the thin Wall of the tube and the fact that it is formedinto a ring, it is very simple to heat the container 2t by means of thehigh freouency coil 23 to burst the tube in the finished device.

- The tube in the assembly has been completely filled with mercury bymeans of a vacuum and accordingly there is no danger of contamination ofthe discharge device because there is no air or a minimum of airincluded in the mercury. The mercury being extended throughout the ringwith a very tiny mass per unit of length prevents the formation of anylarge globule of mercury flying against the glass wall of the containerand breaking it upon the rupture of the tiny ring 26.

The preferred dimensions provide for approximately mg. of mercury ineach inch of length of the tubing, and accordingly the mercury dosagefor the device can be very accurately de termined by the length of thesealed off tube.

In case a larger amount of mercury is desired, I preferably utilize alonger length of tubing, but in this case form the major. part into ahelical coil 21 illustrated in Fig. 5 and then weld the two endstogether at 23.

In some cases, it may be desired to include both mercury and a gaseousmedium in the device. For this purpose I provide a small glass tubing orcontainer 30 illustrated in Fig. 6, and include in this container thegaseous medium in the interior 3| together with the measured amount ofmercury 32 and a metal shot or slug 33. At one end of the container Ipreferably heat up a small area and blow it into the container to form avery thin re-entrant window 3 3. This container 30 may be attached toany convenient portion of the interior structure of the assembled lampor electronic device such as the'press ll. When the device is jarred,the shot or slug 3i) will be driven against the thin window 34 and breakit to release the gaseous medium 3! and the mercury 32 into the tube.

In Fig. '7 I have illustrated a further modification of Fig, 6 in whichthe gaseous medium has been enclosed in the container wall 35 togetherwith the mercury 36. Also in this container is a high expansion wire 31anchored into the wall and then extended in a straight wire 38substantially to the opposite wall and then coiled back on itself in aspring 39, reaching back to the anchor place 40 of the wire. The coilwill be heated by the high frequency device illustrated at 23 in Fig. 1and will expand enough to break the wall 35 of the container and thenrelease the mercury and gaseous medium into the device.

Fig. 8 is a still further modification in which the powerful hairpinspring 41 is so shaped that in the open position the points are widerthan the largest diameter of the enclosing glass bulb 42. Beforeinserting into this bulb, the points are put under compression and heldby a fusible length or loop of fusible wire 43. When the length isheated by high frequency it melts and releases the spring which breaksthe bulb and, in turn, releases the mercury 44 and other desired gaseousmedium included in the bulb 42.

Fig. 9 is a still further modification in which a coil spring 45 is putunder compression and held by a fusible Wire 46 in a shell 41. When thelength 46 is melted by high frequency, the spring 45 will be releasedand fly out of the shell with sufiicient force to break the glass bulbcontainer 48.

In Figure 10 I have illustrated merely the glass bulb 49 with a metalshot 50 and the mercury therein, together with any gaseous mediumdesired. The device may be shaken vigorously so that the shot breaks thebulb and releases the mercury. This particular form. of the inventionis, of course, not adapted with discharge devices having a delicatestructure.

In Fig. 11 I have disclosed a hairpin bimetal 52 inside the bulb 53. Anapplication of heat or high frequency thereto will force it to break theglass bulb and release the mercury 54 and other gaseous medium insidethe bulb.

In Fig. 12 I have illustrated a similar hairpin bimetal 55 but I havealso provided a thin interior' goose neck extension 56 of the wall whichmay be easily broken by the expansion of the bimetal hairpin for therelease of the mercury 51.

In Figs. 6 through 12 I have mentioned the combination of mercury andother gaseous medium inside the containers. This other gaseous mediummay be any one or combination of noble gases, such as argon, neon, etc.In case only mercury vapor is desired inside the tube, then, of course,only mercury would be inserted in the containers illustrated in Figs. 6through 12.

Although I have described certain preferred embodiments of my invention,it is apparent that still further modifications may be made therein, andaccordingly, I desire only such limitations to be imposed on myinvention as are necessitated by the spirit and scope of the followingclaims.

I claim:

1. A casing for the introduction of mercury into a discharge devicecomprising an elongated member having an interior longitudinal chamberand having means closing said chamber at spaced parts thereof, saidspaced closing means being secured externally with respect to eachother.

2. A casing for the introduction of mercury into a discharge devicecomprising an elongated member having an interior longitudinal chamberand having means closing said chamber at spaced parts thereof, saidspaced closing means being juxtaposed one on another and rigidly securedtogether.

3. A casing for the introduction of mercury into a discharge devicecomprising an elongated member having an outside diameter of from 15 to35 mils and a wall thickness of 3 to 6 mils, the ends of said casingbeing closed and secured to each other.

4. A casing for the introduction of mercury into a discharge devicecomprising a tubular casing having flattened ends, said casing beingbent into a loop with said flattened ends thereby brought together andsecured to each other.

5. A casing for the introduction of mercury into a discharge devicecomprising a tubular casing having flattened portions next opposite endsof said casing, said flattened portions of opposite ends being securedtogether.

6. A casing for the introduction of mercury into a discharge devicecomprising a tubular casing having a wall thickness of 3 to 6 mils andhaving flattened ends, said casing being looped with the ends thereofjuxtaposed and secured to each other.

7. An evacuated discharged device having electrodes therein, a tubularcontainer having its ends secured to each other, mercury within'saidcontainer, said container being supported from one of said electrodes.

EDMUND A. REUTER.

